I have a bunch of hermits, I mean a lot (30 gal frag tank with about 60 red & blue leg). Once every 3 weeks I move frag trays to the sand bed and the hermits swarm them leaving them pristine in about 24 hrs (not that they are too bad with a cleaning every 3 weeks). I have tried the peroxide method and is does work but does not eliminate the issue and tends to upset the zoas & palys so I like the hermit method.